[Doc] Update contributor list (vllm-project#10880)

### What this PR does / why we need it?

This PR updates the contributor list in
`docs/source/community/contributors.md` to include the latest
contributors up to commit `edcae83da32af8e1f1b7b97c7e19e8114e0535a5`. It
also refactors the incremental update logic in
`tools/collect_user_first_contribution.sh` to correctly calculate and
assign contributor numbers in descending order and handle old header
skipping more robustly.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

The contributor list was successfully updated using the modified
`tools/collect_user_first_contribution.sh` script.

- vLLM version: v0.23.0
- vLLM main:
vllm-project/vllm@967c5c3

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

Author: wangxiyuan